This invention relates to compounds, compositions, patterned substrates (such as displays and colour filters) comprising these colorants and to methods of making thesame.
The ability to produce brightly coloured patterns or images on substrates, where the colour has high resistance (fastness) to light, water, heat and/or solvents is important in many areas of for instance the electronics and printing industries. Examples of this are in the production of colour filters, in ink-jet printing and in electrophotographic imaging. Thus it is important to discover colorants which can be readily used (and/or formulated into inks for use) in such applications.
Colour filters, alternatively known as optical filters, are a component of coloured liquid crystal displays (LCDs) used as flat screen displays, for example, in small television receivers or portable computers.
Dyes of the following formulae are known: 
Dyes of structures II and III are water soluble monoazo pyridones used as cellulose reactive dyes as described in EP 169,457 B1 (Hoechst). The dye of structure IV is described in GB 1,359,171 (Ciba-Geigy), as a dye for wool or cellulosics. The dye of structure I in which a pyridone moiety is bound to a zinc phthalocyanine is described in JP-A 01-303407 (Nippon Kayaku) as a one component green dye for colour filters. This is different from the present invention in which a yellow dye is used as a separate component of a green ink for colour filters. This offers much greater flexibility in adjusting the precise shade of the ink and also is advantageous over zinc phthalocyanines which are less favoured due to poor light fastness.
Known mixtures of copper phthalocyanines and azopyridone yellow dyes (such as the dyes exemplified in JP2701387B2 [Mitsubishi Kasei Corp]) are unsatisfactory for use in colour filter applications because of poor light fastness. However, green colour filters containing azopyridone yellow dyes are significantly brighter than those produced using alternative yellow chromophores such as azobenzenes, azopyrazolones, metallised azo dyes and yellow pigments, which are prevalent in the art.
It is desirable therefore to find improved colorants for use in colour filters, in particular colorants which can be used either alone for example as a yellow or as a yellow component in a mixture (e.g. with cyan colorants such as phthalocyanines). It is a preferred object of a preferred aspect of the invention to discover a green colorant comprising a mixture of one or more yellow colorants with one or more cyan colorants which is of particular use in a colour filter, optionally with improved properties such as light fastness and/or brightness.
The present invention provides azopyridone compounds of use in preparing patterned colored substrates such as colour filters. The compounds give stable inks with advantageous properties. As a preferred aspect of the present invention the applicant has surprisingly discovered certain simple pyridone dyes containing carboxy groups ortho to the azo linkage have a significant advantage in terms of light fastness versus related ortho-sulpho analogues, with no loss in brightness.
According to the present invention there is provided a composition comprising a solvent and at least one compound of Formula (1) 
in which:
R1 represents H, an optionally substituted C1-8carbyl derived group, or a group of Formula A: 
where:
c is from 2 to 6;
R3 represents H or optionally substituted C1-8carbyl derived group;
R4 and R5 independently represent an optional substituent;
R2 represents an optionally substituted C1-8carbyl derived group;
X, Y and Z independently represent H or an optional substituent group;
M represents H or a cation; and
m and n independently represent 0, 1 or 2.
The azopyridones of Formula (1) are particularly suitable for use in colour filters, giving very bright yellow films with good light fastness, and as components of ink-jet inks. Conveniently compounds of Formula (1) are not pyridinium pyridones (i.e. Z is not pyridinium).
Preferred compounds of Formula (1) are those in which:
R1 represents H, optionally substituted alkyl, a group of Formula [R9O]aR6, or a group of Formula A
R2 represents alkyl, especially C1-4alkyl more especially methyl, or CH2SO3M,
X and Y independently represent SO3M, CO2M, PO3M2, SO2NR6R7, CONR6R7, CO2R6, COR6, alkyl, alkoxy, NR6COR7, halogen, NO2, NR7R8;
where R6 and R7 independently represent H, optionally substituted C1-6alkyl, optionally substituted aryl; and R8 represents R6 or a substituted triazinyl group;
Z represents CN, CONH2, H or CH2SO3M;
R3 represents H or optionally substituted C1-8carbyl derived group;
R4 and R5 independently represent halo, SO3M, NR6R7, OR6 or SR7;
M represents H, alkali metal ion, ammonium, or a quatemary ammonium cation (hereinafter QAC); more preferably M is Li+, Na+, K+ or NH4+;
m, n is 0, 1 or 2;
a is an integer from 1 to 10, more preferably from 1 to 5, especially 2 to 3;and each R9 is independently ethylene or propylene:
with the proviso that at least one of R1 to R8, X, Y or Z comprises a group of Formula SO3M or PO3M2; and the compound of Formula (1) is other than a compound of Formula II, III or IV as described herein.
Preferred QAC""s are those containing C1-30 , alkyl chains. More preferred QAC cations may be selected from one or more of the following: N,N-diethyl-N-dodecyl-N-benzylammonium; N,N-dimethyl-N-octadecyl-N-(dimethylbenzyl) ammonium; N,N-dimethyl-N,N-didecyl ammonium; N,N-dimethyl-N,N-didodecyl ammonium; N,N,N-trimethyl-N-tetradecylammonium; N-benzyl-N,N-dimethyl-N-(C12-18alkyl)ammonium; N-(dichlorobenzyl)-N,N-dimethyl-N-dodecylammonium; N-hexadecyl pyridinium; N-hexa decyl-N,N,N-trimethylammonium, dodecylpyridinium; N-benzyl-N-dodecyl-N,N-bis(hydroxyethyl)ammonium; N-dodecyl-N-benzyl-N,N-dimethylammonium; N-benzyl-N,N-dimethyl-N-(C12-18alkyl)ammonium; N-dodecyl-N,N-dimethyl-N-(1-naphthylmethyl) ammonium and N-hexadecyl-N,N-dimethyl-N-benzylammonium cations.
Suitable QAC cations may also be formed from suitable amines for example from one or more amines selected from: isononylamine, dodecylamine, octadecylamine, didecylamine, didodecylamine, tetradecylamine, hexadecylamine, mixed C12-18alkylamines and N-benzyl amines. Preferred amines which may be used to from suitable QAC comprise N-C1-6alkyl primary amines, N,N-di-C1-8alkyl secondary amines and N-benzyl amines. Particularly preferred amines comprise methyl and ethyl amine derivatives.
Preferably at least one of R1, R2, X, Y or Z comprises a group of Formula SO3M or PO3M2 where M is independently as represented herein; when n is 0; m is 1; X is a sulpho group para to the azo group; Z is H and R2 is methyl then R1 is other than ethyl and the compound of Formula (1) is other than a compound of Formula II, III or IV as described herein.
More preferred compounds of Formula (1) are of Formula (2): 
in which
Z is CONH2, CN or H;
R1 is optionally substituted C2-8alkyl (preferably hydroxy substituted) or a glycol group (for example CH2CH2OCH2CH3 or CH2CH2OCH2CH2OH);
with the proviso that if the SO3M group is in the 4-position of the benzene ring then either R1 is other than ethyl or Z is other than H.
In general, preferred compounds of the invention are those which give particularly bright yellow films and prints, and are easily synthesised from readily available intermediates. Solubility in an aqueous ink is also desirable, hence compounds of Formula (1) comprise at least one SO3M or PO3M2 group, comprise substituent (e.g. R1) of C8 (or less) carbyl-derived groups. To improve solubility optionally R1 comprises at least one PEG and/or OH group.
Compounds of the present invention can be prepared by analogy to any of the methods known in the art, for example as in GB 1,271,226.
According to a further aspect of the present invention there is provided a compound of Formula (1) as hereinbefore defined with the provisos that:
at least one of R1, R2, X, Y or Z comprises a group of Formula SO3M or PO3M2 where M is independently as represented herein;
when n is 0; m is 1; X is a sulpho group para to the azo group; Z is H and R2 is methyl then R1 is other than ethyl; and
the compound of Formula (1) is other than a compound of Formula II, III or IV as described herein.
Preferences for the substituents in Formula (1) are as hereinbefore defined in relation to the composition. Especially preferred compounds of the invention are of Formula (2) as hereinbefore defined.
Preferably the solvent comprises water or more preferably water and one or more water soluble organic solvents.
The viscosity of the composition is preferably less than 100 cp, more preferably less than 50 cp, especially less than 20 cp, more especially less than 15 cp and most preferably less than 10 cp at 20xc2x0 C.
Preferably the composition has been filtered through a filter having a mean pore size below 10 xcexcm, preferably below 5 xcexcm, more preferably below 2 xcexcm, especially below 0.5 xcexcm. In this way particulate matter is removed which could otherwise block fine nozzles in an ink-jet printer.
The composition preferably has a total concentration of divalent and trivalent metal ions, other than those bound to the pigment, below 5000, more preferably below 1000, especially below 100, more especially below 20 parts per million by weight relative to the total weight of the composition. Pure compositions of this type may be prepared by using high purity ingredients and/or by purifying the composition after it has been prepared.
Suitable purification techniques are well known, for example ultrafiltration, reverse osmosis, ion exchange and combinations thereof.
When in the formulae herein there is a list of labels (e.g. Ar1 and Ar2) or indices (e.g. xe2x80x98nxe2x80x99) which are said to represent a list of groups or numerical values, and these are said to be xe2x80x9cindependent in each casexe2x80x9d this indicates each label and/or index can represent any of those groups listed: independently from each other, independently within each repeat unit, independently within each Formula and/or independently on each group which is substituted; as appropriate. Thus in each of these instances many different groups might be represented by a single label (e.g. Ar1).
The term xe2x80x98haloxe2x80x99 as used herein signifies fluoro, chloro, bromo and iodo.
The terms xe2x80x98optional substituentxe2x80x99 and/or xe2x80x98optionally substitutedxe2x80x99 as used herein (unless followed by a list of other substituents) signifies the one or more of following groups (or substitution by these groups): carbyl, carboxy, sulpho, phospho, formyl, hydroxy, amino, imino, nitrilo, mercapto, cyano, nitro, halo and/or combinations thereof. These optional groups include all chemically possible combinations in the same moiety of a plurality (preferably two) of the aforementioned groups (e.g. amino and sulphonyl if directly attached to each other represent a sulphamoyl radical).
The term carbyl as used herein denotes any monovalent or multivalent organic radical moiety which comprises at least one carbon atom either solely (e.g. xe2x80x94Cxe2x89xa1Cxe2x80x94) or optionally combined with at least one other non-carbon atom (e.g. alkyl, carbonyl etc.). The non-carbon atom(s) may comprise any elements other than carbon (including any chemically possible mixtures or combinations thereof) that together with carbon can comprise an organic radical moiety. Preferably the non-carbon atom is selected from at least one hydrogen and/or heteroatom, more preferably from at least one: hydrogen, phosphorus, halo, nitrogen, oxygen and/or sulphur, most preferably from at least one hydrogen, nitrogen, oxygen and/or sulphur. Carbyl groups include all chemically possible combinations in the same group of a plurality (preferably two) of the aforementioned carbon and/or non-carbon atom containing moieties (e.g. alkoxy and carbonyl if directly attached to each other represent an alkoxycarbonyl radical).
Preferably xe2x80x98carbyl-derivedxe2x80x99 moieties comprise at least one of the following carbon containing moieties: alkyl, alkoxy, alkanoyl, carboxy, carbonyl, formyl and/or combinations thereof; optionally in combination with at least one of the following heteroatom containing moieties: oxy, thio, sulphinyl, sulphonyl, amino, imino, nitrilo and/or combinations thereof.
The term xe2x80x98hydrocarbylxe2x80x99 as used herein (which is encompassed by the term xe2x80x98carbyl-derivedxe2x80x99) denotes any radical moiety which consists only of at least one hydrogen atom and at least one carbon atom. A hydrocarbyl group may however be optionally substituted.
More preferably xe2x80x98hydrocarbyl derivedxe2x80x99 moieties comprise one or more of the following carbon containing moieties: alkyl, aryl, alkaryl and/or combinations thereof. The term xe2x80x98arylxe2x80x99 as used herein signifies a radical which comprises an aromatic hydrocarbon ring, for example phenyl, naphthyl, anthryl and phenanthryl radicals. The term xe2x80x98alkylxe2x80x99 or its equivalent (e.g. xe2x80x98alkxe2x80x99) as used herein may be readily replaced, where appropriate, by terms denoting a different degree of saturation and/or valence e.g. moieties that comprise double bonds, triple bonds, and/or aromatic moieties (e.g. alkenyl, alkynyl and/or aryl) as well as multivalent species attached to two or more substituents (such as alkylene).
Any radical group mentioned herein as a substituent refers to a monovalent radical unless otherwise stated. A group which comprises a chain of three or more atoms signifies a group in which the chain may be straight or branched or the chain or part of the chain may form a ring. For example, an alkyl group may comprise: propyl which includes n-propyl and isopropyl; butyl which includes n-butyl, sec-butyl, isobutyl and tert-butyl; and an alkyl group of three or more carbon atoms may comprise a cycloalkyl group. The total number of certain atoms is specified herein for certain substituents, for example C1-nalkyl, signifies an alkyl group having from 1 to n carbon atoms. Preferred alkyl groups in compounds of Formulae (1) and (2) may be branched or straight chain and preferred branched chain alkyl groups are xcex1-branched alkyl groups.
Advantageously the optional substituents and/or carbyl derived groups which may be present in Formula (1) herein may be each independently selected from: carboxy, sulpho, phospho, nitro, bromo, chloro fluoro, alkyl (especially C1-4alkyl) alkoxy (especially C1-4alkoxy), hydroxy, sulphamoyl, amine (especially xe2x80x94NHR10 and NR10Ar), mercapto, thioalkyl (especially C1-4thioalkyl), cyano, ester (especially OCOR10 or COOR10) and amide (especially CONHR10 and NHCOR10);
where R10 is H or optionally substituted C1-6alkyl (especially H or C1-4alkyl) and Ar is an optionally substituted aromatic ring (especially a benzene ring).
More preferred optional substituents and/or carbyl derived groups in Formula (1) are selected from SO3M, CO2M, PO3M2, Cl, Br, F, OH, C1-4alkyl, C1-4alkoxy, CONH2, SO2NH2, OCO(C1-4alkyl), COO(C1-4alkyl), NHAr and NHCO(C1-4alkyl), where M and Ar are as defined herein.
Certain compounds and/or moieties therein (such as repeat units), which comprise the present invention may exist in many different forms for example at least one form from the following non-exhaustive list: salts (e.g. with organic and/or inorganic acids and/or bases including acid and/or base addition salts); isomers, stereoisomers, enantiomers, diastereoisomers, geometric isomers, tautomers, conformers, zwitterions, forms with regio-isomeric substitution, isotopically substituted forms, polymorphs, polymeric configurations, tactic forms, interstitial forms, complexes, chelates, clathrates, interstitial compounds, non-stoichiometric complexes, stoichiometric complexes, ligand complexes, organometallic complexes, solvates, isotopic forms, mixtures thereof and/or combinations thereof within the same species. The present invention preferably comprises all such forms of compounds, polymers, moieties therein, any compatible mixtures thereof and/or any combinations thereof, which comprise the present invention, preferably those which are effective in IJP and/or colour filters.
Salts of Formula (1) may be formed from one or more organic and/or inorganic bases. Preferred salts of Formula (1) are soluble in water.
The inks preferably contain from 1 to 10, more preferably from 1 to 6, especially from 1 to 3, more especially 1 compound of Formula (1).
The compounds of Formula (1) are preferably soluble in water. However, they may be modified to be soluble in organic solvents by use of a QAC as the counter ion, where QAC is as hereinbefore defined.
The compounds of Formula (1) may be prepared by any suitable method known in the prior art.
The composition may contain further compounds other than those of Formula (1), for example to modify the colour or brightness of the ink.
The compounds of Formula (1) may be used individually as part of a YMC (yellow, magenta, cyan) colour filter, or mixed with other compounds as the red or green component of an RGB (red, green, blue) colour filter. The arrangement of pixels could be any of those known in the art (stripe, mosaic, delta) and the filters would be suitable for displays, especially LCD""s, and solid state imaging devices.
Use of the compounds of Formula (1) gives filters with very good fastness properties and brighter than those in the prior art.
The compounds may also be used in an ink-jet printing ink to give bright yellow prints with good fastness properties.
It is another object of the present invention to provide improved inks for processes for forming film coatings, that overcome some or all of the disadvantages of the prior art as discussed above, as well as products made and coated by processes using such inks (in particular colour filters). In particular there is provided a composition according to the first aspect of the invention which is a green, red or yellow ink suitable for use in any of these processes.
Therefore according to another aspect of the present invention, there is provided an ink containing a compound of Formula (1) for use in any process for preparing a patterned, cross-linked, polymer, film coating on a substrate.
It is particularly preferred that the inks of the current invention are used in processes to manufacture a colour filter. These processes may comprise or consist of steps known in methods for producing colour filters (with colorants other than the novel compounds of the present invention). Such processes are well known in the art and include various printing, photolithographic, photographic, electrodeposition, laser ablation and thermal transfer processes. Examples of suitable processes are described below and in the following references, but it is to be understood that the invention is not limited to these processes:
xe2x80x9cReliability Improvements of Dichromated Gelatin Color Filters for TFT-LCD""sxe2x80x9d, A. Endo, E. Hirose, T. Sato, S. Otera, N. Chiba, Polym. Mater. Sci. Eng., 1990, 63, 472-6.
xe2x80x9cProcess and Material for Color Filter Preparation in Liquid Crystal Displayxe2x80x9d, H. Aruga, J. Photopolym. Sci. Technol., 1990, 3, 9-16.
xe2x80x9cColor Filter for Liquid Crystal Displayxe2x80x9d, S. Okazaki, Trans. Inst. Electron. Inf. Commun. Eng., Sect. E, 1988, E71, 1077-9.
P. Gregory, Chapter 2 xe2x80x9cMicro Color Filtersxe2x80x9d in xe2x80x9cHigh-Technology Applications of Organic Colorantsxe2x80x9d, Kluwer Academic/Plenum Publishers, 1991.
xe2x80x9cColor Filters for LCDsxe2x80x9d, K. Tsuda, Displays, 1993, 14, 115-24.
xe2x80x9cPrinting Color Filter for Active Matrix Liquid Crystal Display Color Filterxe2x80x9d, K. Mizuno, S. Okazaki, Jpn. J Appl. Phys., Part 1, 1991, 30, 3313-17.
EP 661350 (=U.S. Pat. No. 5,608,091) (Nippon Shokubai)
EP 833203 (Nippon Shokubai)
It will be appreciated that where the compounds described are not water soluble, the processes described in the references may need appropriate modification to allow the use of the compositions and compounds of the present invention. Alternatively, where the colorants described are solvent soluble dyes, compositions and compounds of the present invention may be used by modification of their solubility in organic solvents through appropriate choice of the counter ion as described previously.
A typical process for preparing a patterned, cross-linked, polymer, film coating on a substrate comprising the steps of
(a) applying to the substrate simultaneously and/or sequentially in any order.
(i) one or more cross-linkable polymer precursor(s);
(ii) optionally one or more additional cross-linker(s) capable of cross-linking the precursor(s) for the polymer(s); and
(iii) one or more compound(s) of Formula (1) optionally with one or more other colorant(s);
(b) optionally patterning one or more non cross-linked film(s) of component (i); component (ii); component (iii) and/or mixture(s) thereof, optionally before application of further components; and
(c) initiating cross-linking the mixture of components (i), (ii) in situ, to form an optionally patterned, cross-linked polymeric film coating on the substrate.
Preferably the application method in step (a) comprises applying an ink comprising both components (i) and (ii).
It is also preferred that the polymer precursor(s) in step (a) (i) above comprise water dissipatable polymer precursor(s). It is especially preferred that these water dissipatable polymer precursor(s) comprise acrylic polymer precursor(s).
A process for which the present invention is particularly suitable is a printing process, especially an ink-jet printing (IJP) process.
Preferably the printing process used is thermal or piezo IJP. The principles and procedures for ink jet printing are described in the literature for example in High Technology Applications of Organic Colorants, P. Gregory, Chapter 9 ISBN 0-306-43637-X.
Other suitable printing methods comprise: flexographic printing; off-set printing [e.g. as described in JP-A-10(98)-088055 (Sumitomo Rubber)] lithographic printing; gravure printing; intaglio printing; dye diffusion thermal transfer, screen and/or stencil printing [e.g. as described in WO 97-048117 (Philips Electronics)] and/or using xe2x80x98typographic ink imaging pinsxe2x80x99 (e.g. as described in WO 97-002955 (Coming Inc.)].
Preferred methods of applying the polymer precursor and compound of Formula (1) to the substrate comprise one or more of the following:
1) print onto the substrate (advantageously by IJP) a mixture comprising the polymer precursor which is thermally cross-linkable and the colorant; and thereafter curing the mixture in situ (e.g. as described in the applicant""s co-pending application GB 9824818.0).
2) Apply to the substrate a polymer precursor which is an anionic colourable photosensitive resin, and then exposing the resin to UV light via a mask to either make the exposed portions, which correspond to the pixels accept colorant; or harden the resin at the exposed portions, which correspond to the black matrix, to make it resistant to colorant; and print onto the resin (advantageously by IJP) a solution of the colorant. [e.g. as described in EP 0703471(Canon)]:
An additional method of applying the ink is by a photolithographic process. This may involve either
1) Apply to a substrate a polymer precursor which is an anionic colourable photosensitive resin; and then expose the resin to radiation (e.g. UV light) through a patterned mask, develop the substrate to remove unexposed portions of the resin, optionally heat to further set the resin, then dip the substrate into an aqueous solution of the colorant. [e.g. as described in U.S. Pat. No. 5,190,845 (Nippon Kayaku)]
2) Apply to a substrate an ink containing a photosensitive resin and the colorant; and then expose the resin to radiation (e.g. UV light) through a patterned mask, develop the substrate to remove either the exposed or unexposed portions of the resin and optionally heat to further set the resin [e.g as described in EP 564237 (Mitsui Toatsu)]
3) Apply to a substrate a non-photosensitive ink containing the colorant and a thermally cross-linkable resin; then apply an ink containing a photosensitive resin over this coloured film; expose the photosensitive resin to radiation (e.g. UV light) through a patterned mask; develop the substrate to remove either the exposed or unexposed portions of the photosensitive resin and the corresponding portions of the coloured film beneath, heat to thermally cure the coloured polymeric film and optionally strip the photosensitive resin that remains [e.g. as described in U.S. Pat. No. 5,176,971 (Kyodo Printing) and WO 88/05180 (Brewer Science Inc.)]
In 1) the photosensitive resin may be either a natural polymer such as gelatin or casein which has been photosensitised by the addition of for example ammonium dichromate, or may be a synthetic polymer.
In 2) and 3) the photosensitive resins used may be of either the positive or negative type. In the positive type, the solubility of the resin in a developing solution increases on exposure to radiation; in the negative type the solubility of the resin in a developing solution decreases on exposure to radiation.
In the laser ablation method, an ink containing a compound of Formula (1) and a (optionally thermally curable) non-photosensitive resin is applied to the substrate, then portions of the substrate are irradiated with a laser beam to selectively remove the ink in those areas through vaporisation and the remaining ink is optionally heated to thermally cure the resin [e.g. as described in JP10274709 (Sekisui Chem Ind.)]
In these processes the inks may be applied to the substrate by any known coating method including spin-coating, bar-coating, dip-coating, curtain-coating, roller-coating and electrospray.
The process of the present invention can be used to give optionally patterned, optionally transparent films and coatings on substrates in general, including substrates which are not transparent. Accordingly the present invention includes a process for preparing polymeric film coatings for substrates in general not just colour filters.
The cross-linked polymeric film coating may be formed on a substrate to which the coating will bond, adhere, absorb or fuse. Preferably (e.g. if the process of the present invention is used to manufacture a colour filter) the substrate is transparent. Suitable transparent substrates include glass; plastics films and plates such as those of polyvinylalcohol, polyester, polyvinylchloride, polyvinylfluoride, polycarbonate, polystyrene, polyamide or polyimide. The substrate may be flexible or may be a flat panel (e.g. as used in many LCD displays). A preferred substrate is glass.
The substrates may be pre-treated to improve bonding, adhesion, absorption, fusion or spreading of the cross-linked polymeric coating on the substrate. Suitable pre-treatments include plasma etching in which the substrate is placed in an oxygen atmosphere and subjected to an electrical discharge or application of an adhesion promoter such as a silane.
An ink suitable for manufacture of a colour filter according to the present invention may be made by any method known in the art and comprise: one or more compounds(s) of Formula (1), one or more solvents and optionally other formulating agents. The inks may in addition contain precursor(s) for cross-linked polymer(s), one or more cross-linker(s) capable of cross-linking the precursor(s), optionally one or more non cross-linkable polymer(s) for improving the film-forming ability of the inks or the properties of the final films and (as appropriate for chemically or photochemically initiated systems) either a radical source, a photopolymerisation initiator or a dissolution inhibitor. An ink coloured in one of the desired colours can be produced with compounds of the present invention and optionally one or more other colorants, typically either yellow, green or red.
Preferably the optionally patterning method in step (b) of the process of the present invention uses electromagnetic radiation, more preferably UV radiation. Optionally to produce a colour filter the pattern formed may comprise of a multiplicity of discrete filter regions (pixels) on a transparent substrate via a single pass ink-jet printing process. Optionally, the transparent substrate has previously been subdivided into discrete pixel regions by any method known in the art (for example formation of a black matrix by photolithography).
The steps of the process of the present invention described herein may be followed for each of the desired colours to form a multi-colour optical filter structure so that the filter structure finally comprises the transparent substrate and a single layer of differently coloured pixels arranged in triads or in any desired groups, each consisting of a predetermined number of differently coloured pixels.
The inks of the present invention are particularly useful for forming the green and red pixels of an additive (red, green and blue [RGB]) colour filter and for forming the yellow pixels of a subtractive (yellow, magenta and cyan [YMC]) colour filter.
A further aspect of the invention provides a process for printing an image on a substrate comprising applying thereto an ink according to another aspect of the present invention, preferably by printing, more preferably by means of an ink jet printer. Preferably the ink comprises solvent (preferably aqueous) and a compound of Formula (1) as described herein.
The ink jet printer preferably applies the ink to the substrate in the form of droplets which are ejected through a small nozzle onto the substrate. Preferred ink jet printers are piezoelectric ink jet printers and thermal ink jet printers. In thermal ink jet printers, programmed pulses of heat are applied to the ink in a reservoir (e.g. by means of a resistor adjacent to the nozzle) thereby causing the ink to be ejected in the form of small droplets directed towards the substrate during relative movement between the substrate and the nozzle. In piezoelectric ink jet printers the oscillation of a small crystal causes ejection of the ink from the nozzle. The term ink-jet printer denotes any device which could use an IJP technique to produce an image.
A further aspect of the present invention provides a substrate which has applied thereon an ink of the present invention as defined herein and/or which has been prepared by the process of the present invention also as defined herein.
The substrate, which is optionally transparent, preferably comprises plastic, metal, glass, paper, an overhead projector slide and/or a textile material. More preferably for a colour filter the substrate is glass. Preferred textile materials for ink jet printing are cotton, polyester and blends thereof. When the substrate is a textile material the process for printing an image thereon according to the invention preferably further comprises the step of heating the resultant printed textile, preferably to a temperature of 50xc2x0 C. to 250xc2x0 C.
According to a further feature of this invention there is provided a colour filter comprising red, green and blue filter elements, or yellow, magenta and cyan filter elements, characterised in that the colour filter carries a compound of Formula (1). Preferably the color filter further comprises a coloured cross-linked polymeric coating on a transparent substrate and/or a transparent, coloured, cross-linked, polymer coating on a substrate prepared by the processes according to the present invention.
More preferably the substrate or colour filter comprises an array of coloured trichromatic elements in which the trichromat is selected from: a red, green and blue trichromat; and a cyan, magenta and yellow trichromat.
Preferably the substrate or colour filter has utility as a component for a coloured display.
A further feature of the invention comprises a display containing a substrate or colour filter prepared according to the present invention. Preferably the display comprises a liquid crystal display.
A further feature of the present invention provides a cartridge suitable for use in an ink jet printer containing an ink according to the invention. Also there is provided an ink jet printer containing an ink according to the invention.
The compounds of the present invention are particularly useful as yellow dyes which form particularly good green colorants when combined with a further cyan dye or pigment. Such compositions are particularly useful to produce a green colour filter For the purposes of the present invention the term xe2x80x98colorantxe2x80x99 as used herein denotes perceptible and/or emissive materials. The term xe2x80x9cperceptible materialxe2x80x9d as used herein includes all dyes and/or pigments and denotes materials which absorb radiation substantially in that part of the electromagnetic (EM) spectrum which encompass the infra red (IR); visible and/or ultraviolet (UV) regions, preferably in a region where the radiation wavelength [xcex] is from about 200 nm to about 800 nm, more preferably in the visible region which is detectable by the normal, unaided human eye. The term xe2x80x9cemissive materialxe2x80x9d as used herein denotes a material which is capable of emitting radiation, preferably EM radiation, more preferably radiation in the IR, visible and/or UV regions of the EM spectrum. Examples of emissive materials comprise fluorescent, phosphorescent and/or radioactive materials.
Therefore broadly in another aspect of the present invention there is provided a coloured composition comprising a compound of Formula (1) or (2) (as described herein) together with one or more cyan or green dye(s) and/or one or more cyan or green pigments(s).
Preferably the cyan or green dye comprises a water soluble metal phthalocyanine, more preferably a copper, zinc, aluminium and/or nickel phthalocyanine. Preferably the composition of the present invention comprises a cyan dyes of Formula (3) 
in which:
T represents H or an optional substituent, preferably H, alkyl, alkoxy, CO2M, SO3M;
V represents CO2M, SO3M or PO3M2, especially meta-CO2M x and y independently represent from 0 to 4, preferably from 1 to 3; and
x+y is from 3 to 5, preferably 4;
where M is as given herein for compounds of Formula (1) herein.
Where the cyan or green colorant is a pigment, preferred pigments include C.I. Pigment Green 7 and C.I. Pigment Green 36.
The colorants of the present invention may also be used as shading components in combination with red, magenta and/or orange colorants to produce good red colorants which are useful for producing a red colour filter.
Therefore, in another aspect of the present invention there is provided a coloured composition comprising a compound of Formula (1) (as described herein) together with one or more red, magenta and/or orange colorant(s), [e.g. dye(s) and/or pigment(s)].
It is also to be understood that one or more further yellow colorant(s), [e.g. dye(s) and/or pigment(s)] other than those of the current invention, may be present in the ink for the purpose of adjusting the shade or enhancing the fastness properties of the ink and the resultant film or image produced using the ink.
Apart from the colorants of the present invention of Formula (1) and (2), compositions, inks, colour filters and processes of the present invention may comprise at least one further colorants to form a colorant mixture.
The further colorants (as well as colorants of the present invention) are preferably compatible with the resultant cross-linked polymer coatings, i.e. the resultant cured films have high transparency. Where the colorant is a dye, preferably the colorant is insoluble in organic solvents and soluble in water, for example the colorant may contain sulpho, phospho or carboxy groups.
If the colorant used is not soluble in the solvent used for the ink, the colorant is preferably present as a fine dispersion, prepared by for example milling the colorant in a solvent in a horizontal shaker in the presence of glass or metal beads and a dispersant. Suitable dispersants may comprise an anionic type (for example lignosulphonates and other sulphonated aromatic species) or a non-ionic type (for example alkylene oxide adducts).
Useful classes of further colorants include azos (including metallised azos), anthraquinones, phthalocyanines, perylenes, quinacridones, diketopyrrolopyrroles, pyrrolines, thiophenedioxides, triphenodioxazines, methines, benzofuranones, benzodifuranones, coumarins, indoanilines, benzenoids, xanthenes, triphenylmethanes, nitros, nitrosonaphthols, phenazines, solvent soluble sulphur dyes, quinophthalones, pyridones, aminopyrazoles, pyrollidines, pyrroles, styrylics, maleimides, triphenazonaphthylamines, styryls, dithienes, azomethines, cyanines, indanthrones, benzimidazolones, isoindolinones, isoindolines and azoics.
The Colour Index International lists suitable dyes and pigments for use as further colorants such as acid dyes, direct dyes, basic dyes, reactive dyes, solvent dyes, disperse dyes and pigments and further examples of acid dyes are given in the Colour Index, 3rd Edition, Volume 1, pages 1003 to 1561, further examples of direct dyes are given in Volume 2, pages 2005 to 2478, further examples of basic dyes are given in Volume 1, pages 1611 to 1688, further examples of reactive dyes are given in Volume 3 pages 3391 to 3560, further examples of solvent dyes are given in Volume 3, pages 3563 to 3648, further examples of disperse dyes are given in Volume 2, pages 2479 to 2742, and further examples of pigments are given in Volume 3 pages 3267 to 3390. These colorants are included herein by reference.
Preferably the further colorant(s) is selected from at least one cyan, green, red, magenta and/or orange colorant which is a dye or a pigment.
Subject to the provisos herein, generally preferred colorants are pigments; or dyes which have substituent groups which aid the solubility of the dye(s) in liquid media used in the process or which aid the solubility of the dye(s) in the final cross-linked polymer matrix.
Preferably the composition is an the ink comprising:
(a) from 0.01 to 30 parts of a compound of Formula (1); and
(b) from 70 to 99.99 parts of a liquid medium or a low melting point solid medium; wherein all parts are by weight and the number of parts of (a)+(b)=100.
The number of parts of component (a) is preferably from 0.1 to 20, more preferably from 0.5 to 15, and especially from 1 to 5 parts. Compound A is preferably an IJP effective compound of Formula (1) more preferably of Formula (2). The number of parts of component (b) is preferably from 99.9 to 80, more preferably from 99.5 to 85, especially from 99 to 95 parts.
When the medium is a liquid, preferably component (a) is completely dissolved in component (b). Preferably component (a) has a solubility in component (b) at 20xc2x0 C. of at least 10%. This allows the preparation of concentrates which may be used to prepare more dilute inks and reduces the chance of the colorant precipitating if evaporation of the liquid medium occurs during storage.
Preferred liquid media include water, a mixture of water and a water miscible organic solvent.
When the medium comprises a mixture of water and an organic solvent, the weight ratio of water to organic solvent is preferably from 99:1 to 1:99, more preferably from 99:1 to 50:50 and especially from 95:5 to 80:20. The liquid medium may comprise water and preferably two or more, more preferably from 2 to 8, water-soluble organic solvents.
The water-miscible organic solvent(s) may comprise any of the following and/or mixtures thereof: C1-6-alkanols, preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n-pentanol, cyclopentanol and/or cyclohexanol; amides, preferably linear amides, for example dimethylformamide and/or dimethylacetamide; ketones and/or ketone-alcohols, preferably acetone, methyl ether ketone, cyclohexanone and/or diacetone alcohol; water-miscible ethers, preferably C2-4ethers, tetrahydrofuran and/or dioxane; diols, preferably alkylene glycols containing a C2-C6 alkylene group; more preferably C2-12diols (for example pentane-1,5-diol, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol); thioglycols preferably thiodiglycol; oligo- and/or poly-alkyleneglycols (for example diethylene glycol, triethylene glycol, polyethylene glycol and/or polypropylene glycol); triols, preferably glycerol and/or 1,2,6-hexanetriol; lower alkyl glycol and polyglycol ethers, preferably C1-4alkyl ethers of diols or monoC1-4alkyl ethers of C2-12diols: {for example 2-methoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy)ethanol, 3-butoxypropan-1-ol, 2-[2-(2-methoxyethoxy)ethoxy]ethanol, 2-[2-(2-ethoxyethoxy)ethoxy]ethanol and/or ethyleneglycol monoallyl ether}; cyclic amides, preferably optionally substituted pyrrolidones (for example 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, caprolactam and/or 1,3-dimethylimidazolidone); cyclic esters, preferably caprolactone; sulphoxides, preferably dimethyl sulphoxide and/or sulpholane.
More preferred water-soluble organic solvents are selected from: cyclic amides (for example 2-pyrrolidone, dimethyl pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone N-(2-hydroxyethyl)-2-pyrrolidone and mixtures thereof.); diols, (for example 1,5-pentane diol, ethyleneglycol, thiodiglycol, diethyleneglycol and triethyleneglycol); C1-6alkyl ethers of diols (for example 2-methoxy-2-ethoxy-2-ethoxyethanol); C1-6-alkyl mono ethers of C2-6-alkylene glycols; C1-6-alkyl mono ethers of poly(C2-6-alkylene glycols); and mixtures thereof.
A preferred liquid medium comprises:
(a) from 75 to 95 parts water; and
(b) from 25 to 5 parts in total of one or more solvents selected from: diethylene glycol, 2-pyrrolidone, thiodiglycol, N-methylpyrrolidone, cyclohexanol, caprolactone, caprolactam and pentane-1,5-diol;
where the parts are by weight and the sum of the parts (a)+(b)=100.
Another preferred liquid medium comprises:
(a) from 60 to 80 parts water;
(b) from 2 to 20 parts diethylene glycol; and
(c) from 0.5 to 20 parts in total of one or more solvents selected from:
2-pyrrolidone, N-methylpyrrolidone, cyclohexanol, caprolactone, caprolactam, pentane-1,5-diol and thiodiglycol;
where the parts are by weight and the sum of the parts (a)+(b)+(c)=100.
When the liquid medium comprises an organic solvent free from water, (i.e. less than 1% water by weight) the solvent preferably has a boiling point of from 30xc2x0 to 200xc2x0 C., more preferably of from 40xc2x0 to 150xc2x0 C., especially from 50 to 125xc2x0 C. The organic solvent may be water-immiscible, water-miscible or a mixture of such solvents. Preferred water-miscible organic solvents comprise any of those described above and mixtures thereof. Preferred water-immiscible solvents comprise aliphatic hydrocarbons; esters (for example ethyl acetate) chlorinated hydrocarbons (for example dichloromethane), ethers (for example diethyl ether) and mixtures thereof.
When the liquid medium comprises a water-immiscible organic solvent, preferably it comprises a polar solvent (for example a C1-4alkanol) to enhance the solubility of the dye in the liquid medium. It is especially preferred that where the liquid medium is an organic solvent free from water it comprises a ketone (especially methyl ethyl ketone) and/or an alcohol (especially a C1-4alkanol, more especially ethanol or propanol).
The organic solvent free from water may be a single organic solvent or a mixture of two or more organic solvents. It is preferred that when the medium is an organic solvent free from water it is a mixture of 2 to 5 different organic solvents. This allows a medium to be selected which gives good control over the drying characteristics and storage stability of the ink.
Ink media comprising an organic solvent free from water are particularly useful where fast drying times are required and particularly when printing onto hydrophobic and non-absorbent substrates, for example plastics, metal and glass.
Preferred low melting solid media have a melting point in the range from 60xc2x0 C. to 125xc2x0 C. Suitable low melting point solids include long chain fatty acids or alcohols, preferably those with C18-24chains, and sulphonamides. The compound of Formula (1) may be dissolved in the low melting point solid or may be finely dispersed in it.
The ink may also contain additional components conventionally used in inks for IJP, for example viscosity and surface tension modifiers, corrosion inhibitors, biocides, kogation reducing additives and surfactants which may be ionic or non-ionic.
In a further aspect of the present invention there is provided a general purpose ink optionally for use in preparing a colour filter, the ink comprising a fluid medium, and one or more compounds of Formula (1) herein. The precursor(s), cross-linker(s) and colorant(s) are as defined previously.
Preferably inks according to the invention are prepared by mixing together (i) a solution of the compound(s) of Formula (1) and optionally water.
The amount of the compound(s) or Formula (1) and solvent contained in the ink will vary according to the depth of shade required. Typically, however, the ink will comprise
(a) from 0.5 to 15 parts, more preferably 0.8 to 10 parts, especially 1 to 8 parts in total of one or more compounds of Formula (1);
(b) from 0 to 90 parts, more preferably from 50 to 80 parts of water; and
(c) from 0 to 90 parts, more preferably 0 to 60 parts of one or more water miscible organic solvent(s); and
(d) other ingredients from 0 to 50 parts, more preferably 0 to 30;
where all parts are by weight and the total number of parts of (a)+(b)+(c)+(d) add up to 100.
The water-miscible solvent may be one or more of those described herein, preferably with a solubility in water at 20xc2x0 C. of more than 50 g/l.
Instead of parts (b) and (c) [the water and water-miscible organic solvent(s)] the ink may comprise one or more water-immiscible organic solvent(s).
Suitable water-immiscible organic solvents include aromatic hydrocarbons, e.g. toluene, xylene, naphthalene, tetrahydronaphthalene and methyl naphthalene; chlorinated aromatic hydrocarbons, e.g. chlorobenzene, fluorobenzene, chloronaphthalene and bromonaphthalene; esters, e.g. butyl acetate, ethyl acetate, methyl benzoate, ethyl benzoate, benzyl benzoate, butyl benzoate, phenylethyl acetate, butyl lactate, benzyl lactate, diethyleneglycol dipropionate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di (2-ethylhexyl) phthalate; alcohols having six or more carbon atoms, e.g. hexanol, octanol, benzyl alcohol, phenyl ethanol, phenoxy ethanol, phenoxy propanol and phenoxy butanol; ethers having at least 5 carbon atoms, preferably C5-14 ethers, e.g. anisole and phenetole; nitrocellulose, cellulose ether, cellulose acetate; low odour petroleum distillates; turpentine; white spirits; naphtha; isopropylbiphenyl; terpene; vegetable oil; mineral oil; essential oil; and natural oil; and mixtures of any two or more thereof.
The water-immiscible solvent preferably has a solubility in water at 20xc2x0 C. of up to 50 g/l.
A further feature of the invention provides a composition comprising a water-dissipatable polymer and a compound of Formula (1). In these compositions the preferred water-dissipatable polymers and dyes are as described in in the following co-pending patent applications WO95/34204, WO99/50326, WO99/50362, WO99/50361, WO00/29493, WO00/37575. These applications are hereby incorporated by reference These applications are hereby incorporated by reference.
Such compositions may be dissipated in water and optionally mixed with further ingredients to give an ink, for example with one or more organic solvents.
The other ingredients may comprise one or more formulating agents conventionally used in inks for example to improve the solubility of colorant in the ink and/or to improve the flow and handling properties of the ink. Thus for example the ink may comprise one or more: humectant(s); rheological agent(s) [such as viscosity modifier(s) and/or surface tension modifier(s), for example wax(es) (e.g. beeswax) and/or clay(s) (e.g. bentonite)]; corrosion inhibitor(s), biocides (such as those available commercially from Avecia Limited under the trade name Proxel GXL or from Rohm and Haas under the trade name Kathon); fungicide(s); kogation reducing additives; IR absorber(s) (such as that available commercially from Avecia Limited under the trade name Projet 900NP); fluorescent brightener(s), (such as C.I. Fluorescent Brightener 179); and surfactant(s) (which may be ionic or non-ionic and include surface active agent(s) wetting agent(s) and/or emulsifier(s) such as those described in McCutcheon""s Emulsifiers and Detergents 1996 International Edition or in Surfactants Europa 3rd Edition 1996 each of which is incorporated herein by reference).
The ink may also comprise radical scavengers and/or UV absorbers to help improve light and heat fastness of the ink and resultant colour filter. Examples of such additives include: 2-hydroxy-4-methoxy-5-sulfobenzophenone; hydroxy phenylbenzotriazole; 4-hydroxy-TEMPO and transition metal complexes (such as nickel complexes of thiocarbamic acids). These additives are used typically in an amount from 30% to 60% by weight of the colorant, and are further described in xe2x80x9cThe Effect of Additives on the Photostability of Dyed Polymersxe2x80x9d, Dyes and Pigments, 1997, 33(3), 173-196 and JP-A-04-240603 (Nippon Kayaku).
For an aqueous ink, the ink preferably has a pH from 3 to 12, more preferably from 4 to 11. The pH selected will depend to some extent on the desired cation for the colorant and the method of application. The desired pH may be obtained by the addition of a pH adjusting agent such as an acid, base or pH buffer. The amount of pH adjuster used will vary according to the desired pH of the ink, but typically a base may be present in an amount of up to 30%. Where a liquid(s) is added to the mixture the printed substrate may be dried by heating or by air drying at ambient temperature to evaporate the liquid before the coating is cured or during curing.